Hydrothermal synthesis, characterization, and influence factors of PbTe nanocrystals

In the present paper, we successfully prepared PbTe nanocrystals in a simple aqueous system via the hydrothermal route employing PbO, Te powders and N₂H₄·H₂O as the starting reactants at 150 °C for 14 h. Some factors affecting the morphologies of the PbTe nanocrystals, such as the reaction temperature, time, the amount of NaOH, sorts of reductants and Pb²⁺ ion sources, were systematically investigated. Experimental results indicated that, under keeping the other experimental conditions constant: raising the reaction temperature, the shapes of the as-obtained PbTe hardly changed, while decreasing the temperature, some PbTe dendrites were obtained; the short reaction time availed to obtain cubes with a hole in the center of each face; more amounts of NaOH were favorable to the formation of regular PbTe nanocuboids. When NaBH₄ was used as the reductant, a large amount of near spherical PbTe nanocrystals was produced; while NaH₂PO₂ was used, many PbTe crystals with hollow framework structures were obtained. When Pb(CH₃COO)₂ was used as the Pb²⁺ ion source, some dendrites made of many irregular particles were generated; while PbSO₄ was employed, many PbTe nanocuboids were produced. A possible formation mechanism of PbTe nanocrystals was proposed based on the experimental results.